Resistor terminal



Dec. 8, 1953 5, BALEs 2,662,151

RESISTOR TERMINAL Filed Jan. 4, 1952 INVENTOR. Max G.B.4L.E5 BY 8 gr TORNE Y5 Patented Dec. 8, 1953 RESISTOR TERMINAL Max G. Bales, Anderson,Ind., assignor to General Motors Corporation, Detroit, Mich., acorporation of Delaware Application January 4, 1952, Serial No. 265,013

3 Claims.

This invention relates to an improved resistor terminal of the kind usedin an ignition system for internal combustion engines.

Resistors for use in the primary circuit of the distributor when usedwith an ignition coil requiring a current limiting resistor should bebuilt into the primary terminal of the distributor and the resistanceshould be completely enclosed so that it would be difiicult to operatethe circuit. Should the resistance unit be a separate item or a part ofthe ignition coil it is possible to wire around it in such a manner thatexcessive current would result in the primary circuit and damage thedistributor points or the coil.

An aim of the present invention is to provide an improved heavy dutyresistor combined with a distributor terminal to form a unitarystructure which is mounted in an opening provided in a distributorhousing.

Further objects and advantages of the present invention will be apparentfrom the following description reference being made to the accompanyingdrawings wherein a preferred embodiment of the present invention isclearly shown.

In the drawing:

Fig. 1 is a wiring diagram illustrating the use of the presentinvention.

Fig. 2 is a sectional view, on an enlarged scale, taken on line 2-2 ofFig. 1.

Fig. 3 is a sectional view taken on line 3-3 of Fig. 2.

Fig. 4 is a sectional view taken on line 4-4 of Fig. 2, but on a largerscale.

Referring to Fig. 1 a combined primary terminal and resistance unit 25embodying the present invention is shown in an ignition circuit for aninternal combustion engine, 2! designates a battery or other source ofcurrent grounded at 22 and connected by a wire 23 to an ignition switchincluding stationary contacts 24 and 2t and a movable contact 25. Thecontact 25 is connected by a wire 2? to one end of the primary winding28 of an ignition coil 30. One end of the secondary winding 29 of theignition coil is connected to the primary winding while the other end isconnected by a wire 3! to the high tension terminal 32 of an ignitiondistributor 33. The other end of the primary coil 2% is connected by awire 34 to a terminal 35 of the unit 20. The terminal 35 is connected toa terminal 36 through a resistance element 31. Terminal 36 is connectedto a lear spring 38 of a circuit breaker lever 39 carrying a contact 40cooperating with a stationary contact 4| grounded at 42. The lever 39includes a rub- 2 bing block 43 of insulating material operated by a cam44.

Referring to Fig. 1, the unit 25% includes a heat conducting metal caseor housing 45 having an end wall 46 formed with an aperture to receive areduced end t; of a heat conducting metal bushing or member 58 which isriveted over the inside of the end at. A body d9 of insulating materialis so shaped as to have an annular flange or collar 56, a reducedsection 5!, and an annular flange or collar 52. The collar is formedwith a recess 53 to house the riveted over portion of the bushing E8.The terminal 3% is a conducting bolt and passes through body 49, by wayof a bore 55. The bolt is provided with a head 55 which is adapted toseat in a recess 5'] in the body 49. The shank of the bolt may beprovided with a portion 5t that is shaped to prevent turning of the bolt3% relative to the body 49 due to jarring and vibrations.

The shank of the bolt 36 passes through an insulating bushing 59 housedwithin the coupling 48. The end of the bushing 48 provides a shoulder6!) against which rest an insulating washer iii. A nut 52 threadedlyengaging the threaded end of the bolt, when threaded home, draws thecollar 52 tightly against the end wall 48.

To prevent the body 49 from turning within, the housing 45, due tojarring and vibrations, the collar 52 is provided with a notch in whichis received a detent or depression formed in the housing 45. The body 49is formed with a slit 6? which communicates with the recess or pocket57. Between the collars 5D and 52 the portion 5i is formed with a spiralgroove 68 to receive the resistance element 3? having one end 3Mextending through the slit 6'! and into the recess 51 and is fixed tothe bolt head 5% in any suitable manner, for example, by soldering. Asto the specific formation of the head of the bolt as shown, in Fig. 4,the head may be formed with a boss Bil having a slot it to receive theend 3711 of the resistance element 3'! and portions of the boss may bestaked over the end 31a. If desired, solder may be used to hold the endwithin the confines of the slot 1E]. The other end ll of resistanceelement 31 is threaded through an angular bore 12 in the terminal 35carried, as shown in Fig. 2 by a closure or disc 13 of insulatingmaterial.

A resilient sheet metal washer 15 is placed adjacent the collar 50. Thecentral aperture of washer 15 is of sufficient size so that it will notengage the riveted over portion 16 of the terminal 35 when the washerengages the collar 50 and the closure 13 is in its complete assemblednal and resistance element unit adapted for use with an electricalapparatus, .rforhexampler anignition timer, which is simpleuin design;ecoe nomical in manufacture and efficient in operation. Thisconstruction makes for compactness and durability and the resistance"element is' re-" siliently supported within the housing '45 andnegatives any separation or breaking of connections between theterminals 35 and 36 and the element.

It will be noted that the reduced orintermediate portion 5| of the-body49 supports the resistance element 31 out of contact from the housing 45and the coupling member 48, but the resistance element 31 issufliciently closerto the housing 45 so that the housing will absorbheat from. the element 3'! when hot, said housing 45 transferring someof the heat to the coupling member 48 which in turn transfers heat to atimer housing 80.

The terminal unit 20 is attached to the timer housing '80 by threadingthe bushing V4!? in a tapped hole Bl provided by the-housing in themanner. shown in Fig: 2. The housing supports a head-82 for the ignitiondistributor 33.

While theembodiment of the present invention as herein disclosed,constitutes-a preferred form, it is to be understood that other .-formsmight be adopted. I

What is claimed is as follows:

1. A terminal assembly foruse with'an electrical apparatus having ametal housing, said assembly comprising the housing, a heat conductingcasing adapted to be supported by the housing, said casing having aclosure of insulatingtmaterial at one end; a. terminal carried by theclosure; a sleeve of insulating material located within the casing andhaving an internal shoulder; a second terminal adaptedto clamp .thesleeve against an internal wall of the casing," said terminal havingahead adapted to engage-the shoulder, I a shank portion extending intothe housing and having a threaded portion and'a nut threadedly engagingthe shank whereby the tightening of the nut clamps the sleeve againstthe casing; means for insulating the second terminal and the nut fromthe casing; a resistance element carried by the sleeve; and means forestablishing electrical contact betweensaid resist- 4 ance element andsaid terminals, said resistance element having its intermediate portionsufficiently close to the casing whereby the casing will be effectivefor absorbing heat emanating from the resistance element when hot.

2. A terminal assembly for use with an electrical apparatus having ametal housing, said assembly comprising the housinm. a heat conductingcasing adapted to be supported by the housing, said casing having aclosure of insulating material at one end; a terminal carried by theclosure a sleeve of insulating material located within the casing andhaving an internal shoulder and having-grooves formed in the exteriorsu1'face.-thereof;..a second terminal adapted to clampthe sleeve-againstan internal wall of the casing, said terminal having a head adapted toengage the shoulder, a shank portion extending into the housing andhaving a threaded portion, and a nut threadedly engaging the shankwhereby the tightening of the nut clamps the sleeve against the casing;means for insulating the sec- 0nd terminal and the nut from thecasing'ya resistance element carried by the sleeve; a resistanee elementwound in said grooves and having its opposite ends passed through a slotinsaid sleeve to the interior of said sleeve; and means for establishingelectrical connection between said ends of the resistanceelement andsaid terminals.

3. A terminal assembly for electrical apparatus having a metal housingprovided with an open,- ing, said assembly comprising the housing; aheat conducting casing having atub'ular extension at the other end, saidextension having to have threaded engagement with the opening of thehousing; a body of insulating material located within the-casing andhaving a counterbored passage therein to provide a.shoulder; a terminalmember adapted to clamp the body against an interior wall of the casing,said terminal member having a head adapted to engage the shoulder withinthe passage of the body, a shank portion projecting through theextension and having a threaded portion, and .a nut threadedly engagingthe threaded shankwhereby tightening of the nut clamps thebody to thecasin means for insulating theshank and nut from the extension; a secondterminalemember carried by theclosure; and a resistance supported on thebody and having electrical connection with each of said terminalmembers.

vMAXGr. BALES;

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,661,019 Thordarson 'Feb: 28, 1928 2,145,629 Nicoud et alJan. 31, 1939 2,391,065 McKinley Dec. 18, I945

